Detection of postlaser vision correction ectasia with a new combined biomechanical index

Vinciguerra, Riccardo; Ambrósio, Renato; Elsheikh, Ahmed; Hafezi, Farhad; Kang, Dukjin; Kermani, Omid; Koh, Shizuka; Lu, Nan‐Ji; Padmanabhan, Prema; Roberts, Cynthia J.; Taneri, Suphi; Trattler, William; Eliasy, Ashkan; Jum, Ikhyun; Lopes, Bernardo; Padmanaban, Vasanthi; Rosetta, Pietro; Rost, Anika; Torres-Netto, Emílio A.; Vinciguerra, Paolo

doi:10.1097/j.jcrs.0000000000000629

Cited by 26 publications

(20 citation statements)

References 29 publications

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“…A recent study has shown that the CBI-LVC is highly sensitive and specific in distinguishing stable from ectatic post-LVC eyes. [ 24 ] The mean ± SD pre-LASIK CBI was 0.29 ± 0.22 and 0.31 ± 0.17 in the Blade and Femto group, respectively, whereas the mean ± SD post-LVC-CBI was 0.07 ± 0.19 and 0.09 ± 0.23 in the Blade and Femto group, respectively, which are within normal ranges suggesting stable corneal biomechanics post-LVC, and thus, no further requirement of treatment. Since both CBI and LVC-CBI follow a different scale, we did not compare pre-op CBI and post-LVC-CBI.…”

Section: Discussionmentioning

confidence: 99%

Short term changes in corneal stress-strain index and other corneal biomechanical parameters post-laser in situ keratomileusis

Kenia

Pirdankar

2021

Indian Journal of Ophthalmology

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Purpose: To report the short-term changes in a corneal stress-strain index (SSI) and other corneal biomechanical parameters post-laser in situ keratomileusis (LASIK) surgery. Methods: A retrospective study was conducted at a tertiary eye care center wherein patients who had undergone LASIK (microkeratome blade and femtosecond bladeless LASIK) between July and December 2019 were enrolled. Patients of age group 20–40 years, best-corrected visual acuity of 20/20, intraocular pressure (IOP) <22 mmHg, pre-LASIK pachymetry >500 microns, and corneal astigmatism ≤3.00 D were included. Subjects with a prior history of refractive surgery, any other ocular or systemic disease, poor-quality scans, intraoperative complications, and missing data were excluded. Corneal biomechanical properties including SSI were analyzed using Corvis ST and compared using the Paired T-test for each group separately at pre-LASIK, and 1-month post-operatively. Results: Overall, 202 eyes were reviewed, and 79 eyes fulfilled the inclusion criteria. Forty-three and 36 eyes had undergone Microkeratome Blade LASIK (Group I) and Femto LASIK (Group II), respectively. Overall, 29 and 26 corneal biomechanical parameters out of 33 changed significantly post-Microkeratome Blade LASIK and Femto LASIK, respectively. Statistically significant changes were noted in all the parameters at A1, maximum and Vinciguerra screening parameters ( P < 0.001), however, no changes were noted in SSI in both the groups when compared with the pre-surgery data. Conclusion: Though the reduction in SSI was not statistically significant, other biomechanical parameters showed significant biomechanical changes pre- and post-LASIK surgeries in both the groups. However, a long-term study with a larger sample size would be required to understand the changes and stability in SSI post-refractive surgery.

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Section: Discussionmentioning

confidence: 99%

Short term changes in corneal stress-strain index and other corneal biomechanical parameters post-laser in situ keratomileusis

Kenia

Pirdankar

2021

Indian Journal of Ophthalmology

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“…In the last years, corneal biomechanics showed to play an important role for the diagnosis and management of keratoconus (5)(6)(7)(8)(9) post refractive surgery ectasia (10), cross-linking effect (11), measurement of intraocular pressure (12,13), and glaucoma (14,15).…”

Section: Introductionmentioning

confidence: 99%

Corneal Biomechanics Differences Between Chinese and Caucasian Healthy Subjects

Vinciguerra¹,

Herber

Wang

et al. 2022

Front. Med.

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PurposeThe aim of this study was to evaluate the difference between Caucasian and Chinese healthy subjects with regards to Corvis ST dynamic corneal response parameters (DCRs).MethodsTwo thousand eight hundred and eighty-nine healthy Caucasian and Chinese subjects were included in this multicenter retrospective study. Subsequently, Chinese eyes were matched to Caucasians by age, intraocular pressure (IOP), and Corneal Thickness (CCT) using a case-control matching algorithm. The DCRs assessed were Deformation Amplitude (DA) Applanation 1 velocity (A1v), integrated radius (1/R), deformation amplitude ratio (DAratio), stiffness parameter at applanation 1 (SPA1), ARTh (Ambrósio's Relational Thickness to the horizontal profile), and the novel Stress Strain Index (SSI).ResultsAfter age-, CCT-, and IOP- matching, 503 Chinese were assigned to 452 Caucasians participants. Statistical analysis showed a statistical significant difference between Chinese and Caucasian Healthy subjects in the values of SPA1 (p = 0.008), Arth (p = 0.008), and SSI (p < 0.001). Conversely, DA, A1v, DAratio, and 1/R were not significantly different between the two ethnical groups (p > 0.05).ConclusionWe found significant differences in the values of the DCRs provided by the Corvis ST between Chinese and Caucasian healthy subjects.

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“…Although linked to pachymetry, its performance appears to be highly independent of pachymetry, as assessed graphically. This result was expected, as the CBI was developed for improving keratoconus diagnosis by combining several indices including the DA, velocity, ARTh, and a stiffness parameter [ 23 , 24 ] Whereas standard indices of the Corvis ST device cannot readily be used for the diagnosis of keratoconus or to demonstrate the effect of CXL in vivo, indices developed in the Vinciguerra screening report—including CBI—allow for a more accurate keratoconus diagnosis compared with standard indices [ 11 , 25 ]. Moreover, the diagnostic ability of the CBI is comparable to that of the Pentacam indices for differentiating normal eyes and eyes with forme fruste keratoconus [ 26 ].…”

Section: Discussionmentioning

confidence: 99%

Comprehensive Assessment of Corvis ST Biomechanical Indices in Normal and Keratoconus Corneas with Reference to Corneal Enantiomorphism

Borderie¹,

Beauruel²,

Cuyaubère³

et al. 2023

JCM

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The aim of this study was to assess Corvis ST biomechanical indices in reference to corneal enantiomorphism. In a prospective observational cohort study, 117 eyes from 63 patients with normal or keratoconus corneas were assessed by three independent observers. In the control group (n = 62), no significant differences were observed between the three observers for all indices. The best reproducibility was obtained with pachymetry and the weakest with CBI. All indices but CBI and arc length featured COV < 10%. All indices except the PD and SSI correlated with pachymetry; all but Rad correlated with IOP. The comparison of the thinnest with the thickest corneas showed no significant differences for any index except pachymetry. In the keratoconus group (n = 55), loss of corneal enantiomorphism was confirmed for all indices except the arc length, velocity, and PD. Significant differences between both groups were found for all indices, even after adjustment for pachymetry and intraocular pressure. The CBI featured the best accuracy (92%), sensitivity (91%), and graphical relevance for keratoconus diagnosis. However, its reproducibility was weak in normal corneas and was strongly dependent on corneal thickness. The SSI was independent of corneal thickness, highly reproducible, and provided the expected enantiomorphism characteristics in both groups, making it a relevant biomarker of biomechanical corneal behavior.

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Detection of postlaser vision correction ectasia with a new combined biomechanical index

Abstract: To validate and evaluate the use of a new biomechanical index known as the Corvis biomechanical index-laser vision correction (CBI-LVC) as a method for separating stable post-LVC eyes from post-LVC eyes with ectasia.

Cited by 26 publications

References 29 publications

Short term changes in corneal stress-strain index and other corneal biomechanical parameters post-laser in situ keratomileusis

Short term changes in corneal stress-strain index and other corneal biomechanical parameters post-laser in situ keratomileusis

Corneal Biomechanics Differences Between Chinese and Caucasian Healthy Subjects

Comprehensive Assessment of Corvis ST Biomechanical Indices in Normal and Keratoconus Corneas with Reference to Corneal Enantiomorphism

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